8o SHELL S. Class VI. 



Marganti- Lin. Sjjt. 1112. Faun. Suec. No. 2130. Li£. Anel. Apt. 

 fir* tab. i. fig. 1. * ** 



18. Pearl. Scheffer Lapland, 145. 



M. with a very thick coarfe opake fhell; often 

 much decorticated ; oblong, bending inward on 

 one fide -, or arcuated ; black on the outfide ; ufual 

 breadth from five to fix inches ; length two and a 

 quarter. Tab. xliii. fig. 18. 



Inhabits great rivers, efpecially thofe which 

 water the mountanous parts of Great Britain. 



This fhell is noted for producing quantities of 

 pearl. There have been regular fifheries for the 

 fake of this pretious article in feveral of our rivers. 

 Sixteen have been found within one fhell. They 

 are the difeafe of the fifth, analogous to the (lone in 

 the human body. On being fqueezed, they will 

 eject the pearl, and often call it fpontaneoufly in the 

 fand of the ftream. 



The Con-way was noted for them in the days 

 of Cambden. A notion alfo pre vales, that Sir 

 Richard Wynne* of Gwydir* chamberlain to Ca- 

 tharine queen to Charles II. prefented her majefly 

 with a pearl (taken in this river) which is to this 

 day honored with a place in the regal crown. 

 They are called by the Weljh Cregin Diluw, or 

 Deluge Shells, as if left there by the flood. ' 



The Irt in Cumberland was alfo productive of 



them. The famous circumnavigator, Sir John 



5 Hawkins* 



